// Quadrilateral.java
 // Class Quadrilateral definition

 public class Quadrilateral
 {
 	private Point point1; 
 	private Point point2; 
 	private Point point3; 
 	private Point point4; 

 	// eight-argument constructor
	public Quadrilateral( double x1, double y1, double x2, double y2,
 		double x3, double y3, double x4, double y4 ) {
 		point1 = new Point( x1, y1 );
 		point2 = new Point( x2, y2 );
 		point3 = new Point( x3, y3 );
 		point4 = new Point( x4, y4 );
 	} // end eight-argument Quadrilateral constructor

 	// return point1
 	public Point getPoint1() {
 		return point1;
 	} // end method getPoint1

 	// return point2
 	public Point getPoint2()
 {
 		return point2;
 	} // end method getPoint2

 	// return point3
 	public Point getPoint3() {
 		return point3;
 	} // end method getPoint3

 	// return point4
 	public Point getPoint4() {
 		return point4;
 	} // end method getPoint4

 	// return string representation of a Quadrilateral object
 	public String toString() {
 		return String.format( "%s:\n%s",
"Coordinates of Quadrilateral are", getCoordinatesAsString() );
 	} // end method toString

 	// return string containing coordinates as strings
 	public String getCoordinatesAsString(){
 		return String.format("%s, %s, %s, %s\n", point1, point2, point3, point4 );

 	} // end method getCoordinatesAsString
 } // end class Quadrilateral